Existing heating, ventilation, and air conditioning (HVAC) systems use hardwired connections as a communication channel to communicate control signals between a thermostat and other HVAC devices. Hardwired connections are reliable. However, relocating the thermostat may be difficult and expensive. Using a wireless connection as a communication channel between a thermostat and other HVAC devices may be susceptible to jamming or interference from other wireless devices. It is desirable to provide a reliable communication channel between a thermostat and other HVAC devices that allows the thermostat to be easily relocated.